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[BUG] Cannot generate certificate from ZeroSSL. listen tcp :56563: bind: address already in use #1117

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[BUG] Cannot generate certificate from ZeroSSL. listen tcp :56563: bind: address already in use#1117
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bugSomething isn't working

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@expressrussian
expressrussian
opened on Apr 14, 2026

My subdomain's certificates have been expired and not auto-renewed. When i create/renew these certificates manually via ACME Tool, it always gives me errors that its IP:port is already in use and it cannot open it for ACME process.

To Reproduce
Steps to reproduce the behavior:

  1. Go to 'TLS/SSL certificates'
  2. Click on 'Open ACME Tool'.
  3. Enter the subdomain, choose ZeroSSL, and click Get certificate.
  4. See error in red popup: "Error: one or more domains had a problem: [mail.domain.eu] [mail.domain.eu] acme: error presenting token: could not start HTTP server for challenge: listen tcp :56563: bind: address already in use"
    I get this type of error also on LetsEncrypt. So, the ACME / http process is not working at all!
  5. If i choose to renew the certificate, the renew button spins indefinitely and does nothing.

Expected behavior
A certificate should be created or renewed and applied.

Screenshots
If applicable, add screenshots to help explain your problem.

Browser (if it is a bug appears on the UI section of the system):

  • OS: Windows 11
  • Browser = Edge
  • Version latest

Host Environment (please complete following information, DO NOT REMOVE ANY FIELD(S)):

  • Arch: [amd64]
  • Device: [Hyper-V VM on Windows 2022 server]
  • OS: Ubuntu
  • Version 24.04
  • Are you using Docker? no
  • Zoraxy Version 3.3.2

Supplementary links
If your issue is related to a particular open source project, paste the link here.

Additional context

  • I use both ipv4 and ipv6. I have restarted the server, same errors. Is this normal that it opens the high ports and not port 80? It is behind NAT, so how it is supposed to work?
  • root@pro:/home/ubuntu# ps aux | grep zoraxy
    root 824 0.0 0.4 7340 3608 ? Ss 08:00 0:00 /bin/bash /zoraxy/zstart.sh
    root 827 0.2 18.0 1464052 154148 ? Sl 08:00 0:06 ./zoraxy -port=:8000
    root 904 0.0 0.6 1229520 5388 ? Sl 08:00 0:00 /zoraxy/plugins/Fail2Ban/Fail2Ban -configure={"port":5867,"runtime_const":{"zoraxy_version":"3.3.2","zoraxy_uuid":"4668b370-5ed4-4c12-9e3b-036b19dc4e46","development_build":false}}
    root 14425 0.0 0.2 6544 2332 pts/2 S+ 08:37 0:00 grep --color=auto zoraxy

I have checked and find that the port in question is already open by zoraxy. I don't know why it tries to reuse it.

Activity

  1. expressrussian
    added
    bugSomething isn't working
    on Apr 14, 2026

  2. tobychui commented on Apr 14, 2026

    @tobychui
    tobychui
    on Apr 14, 2026
    Owner

    There are no one maintaining the ACME module now so I am not quite sure what happens here, but from what I know it should open a random high port and request Zoraxy to forward traffics to it using something call "special routing rules" which are hardcoded in Zoraxy source code and not exposed to user modification.

    You can check out the source code about the acme flow here.

    https://github.com/tobychui/zoraxy/blob/main/src/acme.go

    https://github.com/tobychui/zoraxy/blob/main/src/mod/acme/acme.go

  3. expressrussian commented on Apr 14, 2026

    @expressrussian
    expressrussian
    on Apr 14, 2026
    Author

    After another reboot, in the "Certificates auto renew settings" the spinner is spinning and not giving nothing...
    Or maybe zerossl in no longer provides free certificates???
    Letsencrypt is behaving differently in the Certificate wizard, maybe Zerossl is down?
    When using wizard, i get an error: the server didn't respond to our request (status=pending).

  4. expressrussian
    changed the title [-][BUG] Cannot generate certificate. listen tcp :56563: bind: address already in use[/-] [+][BUG] Cannot generate certificate from ZeroSSL. listen tcp :56563: bind: address already in use[/+] on Apr 14, 2026

  5. tobychui commented on Apr 15, 2026

    @tobychui
    tobychui
    on Apr 15, 2026
    Owner

    @expressrussian Is your TLD supported by ZeroSSL? Seems Russia is in the list.

    Image

    https://help.zerossl.com/hc/en-us/articles/360060119833-Restricted-Countries

  6. Chron-O-John commented on Apr 23, 2026

    @Chron-O-John
    Chron-O-John
    on Apr 23, 2026

    I have the same behavior with both ZeroSSLand LetsEncrypt. And with two different TLDs (.bar and .at)
    It has worked before, but I cannot say if its the 3.3.2 update that broke it or something outside zoraxy.

    Its hosted within its own LXC container with nothing else installed.

  7. hooverek commented on Sep 8, 2026

    @hooverek
    hooverek
    on Sep 8, 2026

    I am having the same problem on 3.3.4 with custom local CA.
    It is as well hosted in LXC container (disabled ipv6)

    The opened ports looks like this:

    tcp6       0      0 [::]:8000               [::]:*                  LISTEN      6645/zoraxy_linux_a 
tcp6       0      0 [::]:5487               [::]:*                  LISTEN      6645/zoraxy_linux_a 
tcp6       0      0 [::]:http               [::]:*                  LISTEN      6645/zoraxy_linux_a 
tcp6       0      0 [::]:https              [::]:*                  LISTEN      6645/zoraxy_linux_a 
tcp6       0      0 [::]:58843              [::]:*                  LISTEN      6645/zoraxy_linux_a 
udp        0      0 0.0.0.0:mdns            0.0.0.0:*                           6645/zoraxy_linux_a 
udp6       0      0 [::]:mdns               [::]:*                              6645/zoraxy_linux_a

    while the interfaces looks as following:

    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: eth0@if165: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether bc:24:11:48:24:fc brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 192.168.3.21/24 metric 1024 brd 192.168.3.255 scope global dynamic eth0
       valid_lft 19340sec preferred_lft 19340sec
176: eth1@if177: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether bc:24:11:9e:f5:20 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 172.16.0.6/24 metric 1024 brd 172.16.0.255 scope global eth1
       valid_lft forever preferred_lft forever

    I think the problem started after enabling 2nd interface (to internal network) but I cannot prove it, as after disconnecting it now zoraxy has similar problems. But before attaching 2nd interface it worked

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